Heart rate monitors and gym machine calorie burn estimates

MadelineTaylah

I'm so disappointed in gym machine calorie burn estimates. I just did my first workout with my new Polar FT7 heart rate monitor and I only burn half of the calories that I thought I did. I never would have thought I would burn so little. -.-

ElleM0

:flowerforyou: Madeline,
Aww.. it's ok! I am learning that alot of the "estimates" are WAY off! Was it a MAJOR difference in numbers?

-Elle

vorgas

The most accurate way to calculate your calories burned is through your VO2 Max. That's the amount of oxygen your body is capable of processing. The higher it is, the lower your heart rate will be at a given exertion level.

Here's a page that lets you determine your VO2 Max: http://www.shapesense.com/fitness-exercise/calculators/vo2max-calculator.aspx

Once you know that, you can plug it into the formula here: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

I highly advise determining your calories burned for 55%, 60%, 65%, 70%, 75%, 80%, 85%. Then just exercise near those zones and you know what your burn will be.

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LOTS OF EXPLANATION ABOUT VO2 MAX AND CARDIO HR

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When you do aerobic exercise, your body mixes oxygen and fat to supply energy to your muscles. Generally speaking, as your heart rate goes up you are using more oxygen, so you are burning more fat. There's lots of mixes and caveats to this, but it's a good generalization for 55% - 70% max HR.

The amount of oxygen you can get is limited by two things: How much you suck in with each breath and how effectively your body can move the oxygen from your lungs to where it's needed.

VO2 Max is the measurement of how much oxygen you can process (Volume of Oxygen - Maximum).

So lets use two women with the exact same stats to calculate a burn:
Both women weigh 150 lbs, are 30 years old, and exercise for 30 minutes at 120 bpm (64% max).
One has a low end VO2 Max of 30 ml per kg of muscle per minute. She burns 152 calories.
The other has a high end VO2 Max of 60 ml per kg of muscle per minute. She burns 234 calories!

Using traditional HR based methods, you would get the same number for both women because all other info is the same. But the one with better VO2 Max is moving more oxygen, so burning more fat.

nettieluvstzu

The same thing happened to me before I got my Polar FT4.. I LOOOOOVE my little device and still till this day get excited to see how hard my body worked for those calories.. lol

1sisrat

I'm so disappointed in gym machine calorie burn estimates. I just did my first workout with my new Polar FT7 heart rate monitor and I only burn half of the calories that I thought I did. I never would have thought I would burn so little. -.-

the gym machine estimates are not accurate. the HRM readings are more accurate. I found the same thing and realized why I was having no progress and needed to push it up a notch. I ended up becoming competative with myself and pushing more by having my Polar FT4! I just had to replace the battery for the first time after 3 years of having it. I bought the replacement batteries on amazon because I couldn't find them locally.

cwolfman13

Yup...one of the reasons I always recommend a HRM; people log way too many exercise calories and then don't get the results they were hoping for based on lousy estimates. Also another reasons I'm not a fan of logging house cleaning and the like.

deminimis

Like anything, machines can be high, low or spot-on. They use established algorithms to come up with an estimated cal burn. I use a Polar HRM and that feeds into my elliptical, which helps. I also understate my weight by at least 10 pounds when entering my info into the machine so as to try and prevent over-estimation (more weight=more cals burned, so less weight will show less cals burned). VO2 max, as stated above, is a great way to get more accuracy as well. I've checked what my machine says, and what the various other calculators state, and they are pretty close. At this stage, I just lower my results to 10 cal/min to be safe (that's me, legs are noodles, feels like I'm walking on Mars when I get off the machine).

MadelineTaylah

On the stationary bike (which i won't be doing much of now) the gym machines said i was burning 400 calories for an hour, where as the hrm says 164. I think the reason why my body must burn so little is because I go on the bike regularly and it's not a hard task anymore. If I go on the elliptical, the calories burnt is much more being around 300 for an hour, however it is still a difference from the machines reading. I knew something was wrong, I have been on a plateu for months. I'm excited now, but also a little angry for all the wasted time.